TEMSTEM

TEMSTEM is an umbrella term for a framework designed to analyze and design complex systems that exhibit dynamics on multiple temporal scales. The acronym stands for Temporal Multiscale Systems Theory and Engineering Method. TEMSTEM draws on dynamical systems theory, multiscale modeling, numerical analysis, and computational simulation to capture interactions between fast microprocesses and slower macroprocesses within a single model. It is used across engineering, physical sciences, and life sciences to study how rapid events influence longer-term behavior and how slower trends modulate faster dynamics.

In practice, TEMSTEM involves separating a system into fast and slow subsystems, applying scale-aware modeling techniques, and coupling the subsystems through interfaces that preserve essential dynamics. The approach emphasizes modular design, where components are analyzed at suitable time resolutions and then integrated to form a coherent whole.

Common methods include time-scale decomposition, multi-rate or multi-time-step integration, reduced-order modeling, adaptive time stepping, and event-driven simulation. Uncertainty quantification and sensitivity analysis are often incorporated to assess how errors at one scale propagate to others and to guide data collection and model refinement.

Applications span climate and environmental modeling, materials science, energy and infrastructure systems, biomechanics, and economic dynamics, where processes such as chemical reactions, phase changes, market transactions, or control actions operate on very different time scales but shape long-term outcomes.

Limitations include high computational cost, challenges in validating multiscale models with data, identifiability of parameters across scales, and the need for standardized benchmarks and best practices to compare methods.